The invention relates to an apparatus for separating and sorting particles flowing in a suspension through chambers having multiple detection means. These detection means may be electrodes which receive current pulses produced when particles pass a measuring orifice and correspond to preset criteria.
More particularly, the invention relates to an apparatus of the above described type in which liquid drops containing the selected particles are provided with a static charge and are subsequently deviated in an appropriate way to enter collection stations for analysis. The deviation may be by electrical and/or magnetic means.
Particle sorters and separators of this type, in which particles are identified and separated according to the Coulter Principle are known and are described for example in U.S. Pat. No. 3,380,584, U.S. Pat. No. 3,710,933 and in various articles in the professional literature, for example Steinkamp, et. al., "A New Multiparameter Separator for Microscopic Particles and Biological Cells," Rev. Sci. Instrum., Vol. 44, No. 9, September 1973, p. 1301-1310; Fulwyler, "Electronic Separation of Biological Cells by Volume", Science, Vol. 150, Nov. 11, 1965, p. 910-911.
It is a basic fault of the known particle separators that the measuring current circuit between the two main electrodes picks up spurious and disturbing pulses from various sources. In spite of sometimes very expensive shielding it has heretofore been impossible to completely eliminate these spurious disturbances. An attempt to overcome this problem is described for example in U.S. Pat. No. 3,710,933, column 7, lines 60-63.